The data in this section gives information about how insert and update operations affect indexes on allpages-locked tables. For example, an insert to a clustered table with three nonclustered indexes requires updates to all three indexes, so the average number of operations that resulted in maintenance to nonclustered indexes is three.
However, an update to the same table may require only one maintenance operation—to the index whose key value was changed.
“Ins/Upd Requiring Maint” reports the number of insert and update operations to a table with indexes that potentially required modifications to one or more indexes.
“# of NC Ndx Maint” reports the number of nonclustered indexes that required maintenance as a result of insert and update operations.
“Avg NC Ndx Maint/Op” reports the average number of nonclustered indexes per insert or update operation that required maintenance.
For data-only-locked tables, inserts are reported in “Ins/Upd Requiring Maint” and deletes and inserts are reported in “Upd/Del DOL Req Maint.”